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Revolver Pusher type Autogyro trainer


Richard Harris
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Don't know if many of you chaps have seen this great bit of film from 1931 (love the haircut - quite modern) what's interesting is how the aerofoil of the machines blades looks to be almost symetrical  and how much more in the way of having a higher aspect ration compared to our models. The machine in the film also shows a pronounced coning angle of the blade disc - not so noticeable with models? Scale effects coming into play?

Edited By Cuban8 on 21/08/2019 09:35:35

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It was a pleasure meeting Dave with his Nellie Revolver last weekend st the Nationals.

No issues were encountered, all that was required was a few clicks of rudder trim. Dave was soon doing circuits for the first time and I think he was pleased with his results.

Unfortunately I only had my phone on me but I did grab a few photos and a minutes worth of footage.

 

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Edited By Richard Harris on 26/08/2019 21:15:10

Edited By Richard Harris on 26/08/2019 21:15:29

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Richard, to say I was pleased is a bit of an understatement! To see it flying and to have a couple of flights myself was a real buzz. I can't thank you enough for designing and developing the Revolver and for sharing it with us through the forum and the magazine. Thank you also for taking the time on Saturday to check Nellie out and trim it for me. To anyone hesitating about building a Revolver, go on, take the plunge. You'll love it. It is a little different to flying a fixed wing aircraft but not that difficult (can't be, I flew mine and landed it in one piece) and is quite addictive. I'm hoping for a couple more flights tomorrow.

It was a great pleasure to meet you, Richard, and thanks again for the help and encouragement.

Regards,

David

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Richard, sorry to be a pain but a bit of advice, please. I tried to fly "Nellie" again yesterday and could not get the rotor up to speed. There was very little wind but our patch is quite long and no amount of taxiing would get the rpm sufficient to take off. After Saturday I found one of the servo arms had cracked (probably that last "landing" and replaced them with ones a little shorter. The blades just clear the rudder at full back stick so I don't think I'm short of movement. Any ideas?

Regards,

David

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David,

If your blades are close to the fin when tilted right back then that is more than enough for them to spin up with a slow taxi into wind.

On Saturday they did seem to take a little longer to get to full RPM, once in the air they were fine with lots of lift. What I would do is add extra shim to each blade, only thin shims, I find that masking tape works ok.

Try that and see if this improves spin up? you will find that by adding extra shim you may need to add a click of extra rearward tilt.

You could also try hand launching? I know Chris from down under swears by this, I'm sure he made a video of how he does it too.

Talking of videos here is the small amount of footage I captured of your first flight with an autogyro including the landing.

Rich

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Hi Mike,

With a 3 blade rotor system I aim for an aspect ratio of around 10:1, length is determined by the weight of the model and whether I want it to fly lightly loaded or not, this aspect ratio increases with 2 blades with a like for like model as you need an increase in blade length.

When I first started messing most were using a Clarke Y aerofoil or a similar section with a chamfered lower TE. Through experimentation (and a bit of luck) I came up with a section that has a sharp LE, this is what I use on pretty much all my models from about 2010. They have a good spin up, plenty of lift and above all are easy to make.

Rich

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Resistance is futile Trevor, you will have that together before the winter is set in!

Here is where I'm at with my second Revolver, fin only with a cranked boom giving me room to lower the motor.

The blue canopy may not be fitted as I'm awaiting a vac formed version from SARIK hobbies off my plug.

 

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Edited By Richard Harris on 31/08/2019 21:17:07

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It's amazing how that cranked boom changes the appearance. Of course if you're leaving out the horizontal stab then the plan view will be very different too.

I have a canopy on order from Sarik. Having failed to find a suitable pilot, I'm contemplating just painting (or at least tinting) the canopy and forgetting about the interior. Motor and ESC are also on order and hopefully, with a bit of improvisation, most of the other bits will be from stock.

And, to complete the confession, I did get the glue pot out yesterday!

Trevor

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  • 5 weeks later...

Nice one Trevor. My Revolver is 95% complete but other distractions have slowed the finish and delayed the first flight. I tinted my pop bottle canopy with Tamiya smoke canopy (model car body ) spray. Works really well and you can adjust the depth of tint to your exact taste. A facinating build that's introduced so many new skills to be mastered and that's without the flying!  See that you've been at the gyros for a while - so not so much of a culture shock for you laugh

You went with balsa for the tail.............I've never used depron before and I'm amazed at it, so easy to use and dead easy to sand to shape. I found a tin of red acrylic in my LMC  that matched the Ferrari Red Profilm that I used on the rest of the fuz - the depron took the colour very well. Will certainly be incorporating it into other builds where appropriate.

 

 

Edited By Cuban8 on 01/10/2019 10:04:28

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Thanks for the response Cuban. Interestingly I’ve been given a can of Tamiya Smoke by a car racing friend. I’m usually a disaster area when it comes to paint so any tips you have on applying it would be much appreciated. I was thinking of masking the outside of the canopy with cling film in the hope that it might make it easier to see how the colour is building up. However I’m not sure how to hold the canopy open to spray the inside.

Trevor

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Both mine are with Depron tails covered completely in film, not at issue at all, just need to get the iron temp correct.

Balsa I am sure will be fine but maybe the resultant weight could be higher than depron.

Both my models needs nose weight and with a balsa tail it would have probably needed more.

Great build log Trevor yes

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Motor view

Steve

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Posted by Trevor on 01/10/2019 10:23:54:

Thanks for the response Cuban. Interestingly I’ve been given a can of Tamiya Smoke by a car racing friend. I’m usually a disaster area when it comes to paint so any tips you have on applying it would be much appreciated. I was thinking of masking the outside of the canopy with cling film in the hope that it might make it easier to see how the colour is building up. However I’m not sure how to hold the canopy open to spray the inside.

Trevor

First time I've used canopy spray, so I sort of made it up as I went along. I took care to clean the canopy of grease and finger marks with Washing up liquid and simply held the canopy by hand on the outside. Built up the depth of colour to what I wanted and that took around five very light coats. I didn't need to hold the canopy open any more than what it was naturally and the spray found its way inside ok. Does look good, will post a pic when I get a moment.

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Posted by Gary Fentiman on 02/10/2019 15:05:41:

This looks like a great build Anyone know where I can get a set of plans from please?

Gary,

Sometimes back issues are still available which include the plan and write up, best person to guide you in the right direction is David Ashby, if he doesn't see this send him a PM.

Failing that Sarik hobbies sell the plan, part kit and canopy if you look HERE.

Rich

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  • 3 weeks later...

Well, my Revolver is finished - colour scheme inspired by Steve J’s example.

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I took it to the field today, the main aim being to see if the head would spin up without any shims under the blades. With practically no wind, it took a long slow takeoff run but the head got going and it did its first brief hop. There was no sign of any rolling or instability so I brought it back for another go. Again the blades spun up okay and it lifted off smoothly. However it immediately became clear that I was holding the stick hard back to hold the nose up, so I settled it back on the ground again. Apart from that, it felt very stable, albeit for a flight of what must have been all of three seconds!

Im pretty sure that the head angle is set more or less right (at right angles to the mast). The hang angle is though at the upper end of the recommended range i.e. on the nose heavy side. So my plan is to move the battery back an inch or so, extend the pushrods slightly then have another go.

Any other suggestions or recommendations.

Trevor

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